Problem: Khan.scratchpad.disable(); For every level Tiffany completes in her favorite game, she earns $380$ points. Tiffany already has $140$ points in the game and wants to end up with at least $3420$ points before she goes to bed. What is the minimum number of complete levels that Tiffany needs to complete to reach her goal?
Explanation: To solve this, let's set up an expression to show how many points Tiffany will have after each level. Number of points $=$ $ $ Levels completed $\times$ Points per level $+$ Starting points Since Tiffany wants to have at least $3420$ points before going to bed, we can set up an inequality. Number of points $\geq 3420$ Levels completed $\times$ Points per level $+$ Starting points $\geq 3420$ We are solving for the number of levels to be completed, so let the number of levels be represented by the variable $x$ We can now plug in: $x \cdot 380 + 140 \geq 3420$ $ x \cdot 380 \geq 3420 - 140 $ $ x \cdot 380 \geq 3280 $ $x \geq \dfrac{3280}{380} \approx 8.63$ Since Tiffany won't get points unless she completes the entire level, we round $8.63$ up to $9$ Tiffany must complete at least 9 levels.